Vtol propulsion system

ABSTRACT

A propulsion system is described which comprises two tip-turbine driven fan units pivotally mounted in a pod. For vertical propulsion the units are respectively registered with vertically aligned inlet and discharge ports in the pod. For forward propulsion the units are swung into registration with a horizontal passageway through the pod.

United. States Patent Timperman 1 Oct. 24, 1972 [54] VTOL PROPULSIONSYSTEM 8,066,890 12/1962 Price .244/12 c 1 3,179,353 4/1965 Peterson..244/12 B [72] Invent g 'f 3,347,496 10/1967 Opfer, Jr. ..244/53 B [73]Assignee: General Electric Company Primary Examiner-Andrew H. FarrellAttorney-James M. Kipling, Frank L. Neuhauser, [22] Flled July 1 OscarB.Waddell and Joseph B. Forman [21] Appl. N0.: 51,923

[57] ABSTRACT 52 US. (:1 ..244/12, 244/23 A Propulsion System isdescribed which comprises two 51 1111.121. ..B64C 15/00, B64c 29/00tip-turbine driven fan units Pivotally mounted in a 5 Field f Search244/12 23 52 5 53 12 A pod. F0! vertical Pl'OPlllSiOll the units arerespectively registered with vertically aligned inlet and discharge [56]References Cited ports in the pod. For forward propulsion the units areswung into registration with a horizontal passageway UNITED STATESPATENTS through the pod.

3,488,018 1/1970 Johnson .244/12 A 8 Claims, 9 Drawing Figures if /6 l.92 h .54

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EUGENE L. TIMPERMA N Arromvd-F PATENTED [1U 24 3 3.700.189

SHEEI 2 [IF 3 s a 34 v I 32 J4 Jfl INVENTO R.

EUGENE L TIMPERMAN While many proposals have been made to providevertical propulsion for fixed wing aircraft, none had any substantialmeasure of commercial success. This may be attributed to variousshortcomings. Where separate powerplants are employed for vertical andforward propulsion, expense and weight have been prime problems. Whenvectorable nozzle have been considered, complexity has been a deterrentfactor. Where powerplants have been swiveled relative to the aircraft,

compromises between the differing aerodynamic requirements for verticaland forward propulsion have made the overall system uneconomical.

In this last regard, it will be noted that forward propulsion is moreefficient where a relatively high pressure rise is imparted to themotive fluid stream. For vertical propulsion, a high mass flow in themotive fluid stream is more important than its pressure rise or pressureratio. Other compromises are also found in the inlet and nozzle areas.where the different modes of operation dictate differingconfigurations. Accordingly, one object of the invention is to pro Ivide an improved propulsion system having a relatively high mass flowfor vertical propulsion and a high pressure rise for forward propulsionof winged aircraft.

' Another object of the invention is to additionally provide inlets andnozzles which are specifically suited for the differing requirements ofvertical and forward propulsion.

These ends are broadly attained by a propulsion system comprising twoormore air pressurizing units which pressurize separate air streams forvertical propulsion and a single air stream for forward propul- SlOn.

More specifically, these air pressurizing units are mounted in a podhaving a horizontal passageway with a thin edged inlet at one end and adischarge nozzle at its other end. The units have ducts which areregistered with vertically aligned inlet and discharge ports in thevertical mode. In the forward mode, these ducts are registered with thehorizontal passagewayof the pod. The inlet ports may be rounded forefficient vertical propulsion.

Preferably the air pressurizing units comprise fans having tip-turbinesdriven from remote gas generators. Special features are provided forhandling the hot gas discharge from the units and .also fortransitioning between vertical and forward propulsion.

The. above and other related objects and features of the invention willbe apparent from a reading of the following description of thedisclosure found in'the accompanying drawings and the novelty thereofpointed out in the appended claims.

In the drawings:

FIG. 1 is a fragmentary perspective view of an aircraft incorporating apropulsion system embodying the present invention and illustrating it ina vertical flight mode;

FIG. 2 is a section, on an enlarged scale, taken on line II--II in FIG.1;

FIG. 3 is a section, on a further enlarged scale, taken on line III-IIIin FIG. 2;

FIG. 4 is a perspective view similar to FIG. 1 illustrating thepropulsion system in its forward mode;

I FIG. 5 is a section taken on line V--V in FIG. 4;

FIG. 6 is a section, on an enlarged scale, taken on line VI -VI in FIG.5;

FIGS. .7 and 8 are sections similar to FIGS. 2 and 5 illustratingtransition between vertical and horizontal driven by a pair of gasgenerators 22 mounted at the forward end of the pod 16. 1

Each of the units 18 and 20 comprises a central frame structure 24 whichis supported on a casing 26. 4

The casing 26 has a central duct 28 and an outer sphericalsurface 30which is received by a corresponding surface formed in the pod 16.Trunnions 32 mount the casings for pivotal movement on the pod l6.Actuators 34 are provided to rotate the units 18 and 20 as will later bedescribed.

The units 18 and 20 each further comprise a rotor 36 having fan blades38 projecting therefrom and outlet guide vanes 40 also supported fromthe casing 26. The hot gas streamfrom one of the gas generators 22 isdischarged into alongitudinal passageway 42 (FIGS. 3 and 6) and passesthrough the trunnion 32 to a scroll 44 formed in the casing 26. Scroll44 directs the hot gas stream to turbine blades 46 secured to the outerends of the fan blades 38. The rotor 36 is thus rotated so that the fanblades 38 pressurize air entering through the passageway 28 anddischarge the pressurized air through the outlet guide vanes 40 toprovide a propulsive force. The hot gasstream, after being dischargedfrom the turbine blades 46, is directed through outlet guide vanes 48and then a concentric outlet passageway 50.

The left fan unit 20 is similarly powered by the discharge of the othergas generator 22 which is directed through a longitudinal passageway 52to the hollow trunnion of that unit. The construction of the units maybe identical and like reference characters are employed to identify likecomponents. It will also be pointed out that the tip-turbine driven fansare well known per se so that further description of these airpressurization devices is not required.

In the vertical mode of propulsion, the units 18 and 20 are positionedwith their axes vertically disposed and with their ducts 28,respectively, in registration with inlet ports 54 in the top of the podl6 and also in registration with discharge ports 56 in the bottom of thepod 16. Cover 58 for the inlet ports 54 is opened in the vertical flightmode by actuators 55 through a mechanical connection 57. Covers 60 forthe discharge ports 56 are swung to open positions for the vertical modeby actuators 59 through a mechanical connection 61. It will also be seenthat struts 63 support the covers 60. I

Referencing next FIGS. 4 7, it will be seen that the pod 16 has acentral passageway 62 with which the vide the forward propulsive force.The hot stream discharge of the unit 18, through the concentricpassageway 50, is directed through a passageway 66 in the pod 16 so thatit is angled outwardly along the outerdownstream surface of the pod 16.Passageway 66 extends circumferentially around the pod a limited angulardistance to preventdischarge of hot gases toward the wing 14.. v

FIGS. 7 9 illustrate transition of the propulsion system from verticalto horizontal operation. The first step is to progressively swing thelower covers 60,

which function as vanes orflaps, rearwardly so that a lustrated in FIG;7. Next, the fan unit 18 is pivoted to a horizontal position asillustrated in FIG. 8. The pressurized air from this unit then bypassesthe unit 20 by being discharged through passageways '68 formed on thesides of the pod 16. In forward propulsion, flaps 72 are respectivelyaligned with the flowpath of the podand the outer surface of the pod.During transition, these flaps are swung open about their upstream pivotpoints by actuators 74 through amechanical linkage 76 which isdiagrammatically illustrated. Aerodynamic forces could, in some cases,obviate the need of actuators to swing the flaps 70, 72. The passageways68 function as nozzles so that the air discharged therefrom contributesto theforward thrust of the system.

After the aircraft has gained sufficient forward speed for the wings 14to provide necessary lift, fan 20 is 2 horizontal forward thrustcomponent is produced as ilrapidly rotated into its horizontal postureand then the covers 58 and 60 for the fan unit 20 are closed as are theflaps 70, 72, returning thepropulsion system to the position illustratedin FIGS. 4 6.

It will be apparent that the described propulsion system provides a highmass flow with a relatively low pressure ratio during verticalpropulsion and a higher pressure ratio and lower mass flow for efficientforward propulsion. Further, the inlet and discharge ports 54 and 56 forvertical propulsion are independent of the inlet and nozzle for forwardpropulsion. This enables the use of bellmouth inlets for better verticalperformance and a sharp edge, high speed inlet for better forwardperformance. Likewise, the discharge ports or nozzles 56 can have theproper area for vertical propulsion while the nozzle 64 has the properarea for forward propulsion. Also, by conforming the covers 58 and 60 tothe cylindrical shape of the pod, more efficient forward propulsion isobtained.

While a preferred embodiment has been disclosed, variations thereofwithin the broader aspects of the invention will occur to those skilledin the art. For example, the fan or air pressurizing units could haveselfcontained gas generators, asfor example, after the nature of aturbofan engine, or in certain aspects a turbojet engine. Dependent onthe aircraft configuration,

. there could be one or a number of propulsion systems and the pod couldhave other than a cylindrical shape. The pod could contain any number ofpropulsion units similarly arranged.

In transitioning, the rear fan unit could be in a horizontal positionwhile the forward unit is in a vertical position. In this case,,theforward unit would be aerodynamically bypassed by opening passageways inthe pod to introduce air to the second unit.

Having thus described the'invention, what is claimed as novel anddesired to be secured by Letters Patent of the United States is:

1. A propulsion system comprising:

a pod'having a horizontal passagewaytherethrough with an air inlet atone end, a nozzle at the other end, and first and second pairs ofvertically aligned inlet and discharge ports opening to and from saidhorizontal 1 passageway, said pairs of ports being spacedapartintermediate the inlet and nozzle, the inlet ports being formed onrelatively large radii after the nature of a bellmouth, and the inlet tosaid pod passageway being relatively sharp for eff cient entry of air athigh speed forward propulsion,

first and second'air pressurizing units, each having a duct throughwhich air flows as it is pressurized,

and i means for selectively registering the ducts of the first andsecond units respectively with the first and second pairs of portsforvertical propulsion and registering the ducts of both units with thehorizontal passageway for forward propulsion.

2. A propulsion system as in claim 1 wherein:

the means for selectively registering said ducts includes means forpivotally mounting said units on said pod and means for pivoting saidunits on their pivots between vertical and horizontal positions.

3. Apropulsion system as in claim 2 further comprismg: I

vane means in the discharge port which are pivotally mounted about axesperpendicular to the direction of forward thrust,

means for pivoting the vanes from a generally vertical position when thepressurizing units are in a vertical position to an angled position intransition-' ing from vertical propulsion to horizontal propulsion; i

means for pivoting one of said units to its horizontal position duringsuch transition while the other unit remains in a vertical positionblocking said horizontal passageway, and

means for aerodynamically bypassing the horizontal unit past thevertical unit during such transition.

4. A propulsion system as in claim 3 wherein:

said one unit is the upstream pressurizing unit moved to a horizontalposition during transition, and

the bypassing means comprise passageways extending at a low anglethrough said pod to its exterior intermediate said units, flap meansnormally closing the bypass passageways and means for swinging said flapmeans outwardly to provide said bypass function.

5. A propulsion system as in claim 2 wherein each of said units comprisea casing and v the means for pivotally mounting said units includestrunnion means having axes disposed at the intersection of the axes ofsaid pod passageway and said ports, and

' the pod, its passageway, the ducts and ports are circular in crosssection; and

the sealing means are spherical.

7. A propulsion system as in claim 2 wherein:

each of said units comprises a casing, a gas generator mounted remotelytherefrom, a fan rotor having a tip-turbine, means for ducting hot gasesfrom the gas generator to the tip-turbine and an annular discharge fromthe tip-turbine for the hot gases,

and further including passageway means in said pod with which theannular discharge of the upstream unit is registered in the horizontalposition of the unit, thereby discharging the hot gases thereof to theexterior of the pod, and

the annular discharge of the downstream unit is registered with the podpassageway in the horizontal position of that unit.

8. A propulsion system as in claim 7 wherein:

the pod, its passageways, the ducts and the ports are circular in crosssection,

the inlet ports are formed on a relatively large radii after the natureof the bellmouth,

the inlet to said pod passageway is relatively sharp for efficient entryof air at high speed forwardpropulsion, the means for pivotally mountingsaid units includes trunnion means having axes disposed at theintersection of the axes of the pod passageway and said ports, and vfurther including spherical means for sealing said unit ducts from saidports when they are registered from said pod passageway and sealing saidducts from said pod passageway when they are registered with said ports,a

covers forsaid ports which conform to the outer surface of said pod,

means for pivoting inlet port covers to open positions when the unitsare in their vertical positions, means for pivoting the discharge portcovers about axes perpendicular to the direction of forward thrust whenthe-units are in their vertical positions,

means for pivoting the discharge port covers in a rearward positiontoward a closed position so that they function as vectoring flaps intransitioning between vertical and horizontal propulsion,

' means for pivoting the upstream unit to a horizontal position duringsuch transition while the other unit remains in a vertical positionblocking said pod passageway,

bypass passageways extending at a low angle through said pod to itsexterior intermediate said units to direct the fan discharge from theupstream unit to the exterior of the pod during transition,

flap means normally closing the bypass passageways and means forswinging said flap means outwardly to provide said bypass function.

1. A propulsion system comprising: a pod having a horizontal passagewaytherethrough with an air inlet at one end, a nozzle at the other end,and first and second pairs of vertically aligned inlet and dischargeports opening to and from said horizontal passageway, said pairs ofports being spaced apart intermediate the inlet and nozzle, the inletports being formed on relatively large radii after the nature of abellmouth, and the inlet to said pod passageway being relatively sharpfor efficient entry of air at high speed forward propulsion, first andsecond air pressurizing units, each having a duct through which airflows as it is prEssurized, and means for selectively registering theducts of the first and second units respectively with the first andsecond pairs of ports for vertical propulsion and registering the ductsof both units with the horizontal passageway for forward propulsion. 2.A propulsion system as in claim 1 wherein: the means for selectivelyregistering said ducts includes means for pivotally mounting said unitson said pod and means for pivoting said units on their pivots betweenvertical and horizontal positions.
 3. A propulsion system as in claim 2further comprising: vane means in the discharge port which are pivotallymounted about axes perpendicular to the direction of forward thrust,means for pivoting the vanes from a generally vertical position when thepressurizing units are in a vertical position to an angled position intransitioning from vertical propulsion to horizontal propulsion; meansfor pivoting one of said units to its horizontal position during suchtransition while the other unit remains in a vertical position blockingsaid horizontal passageway, and means for aerodynamically bypassing thehorizontal unit past the vertical unit during such transition.
 4. Apropulsion system as in claim 3 wherein: said one unit is the upstreampressurizing unit moved to a horizontal position during transition, andthe bypassing means comprise passageways extending at a low anglethrough said pod to its exterior intermediate said units, flap meansnormally closing the bypass passageways and means for swinging said flapmeans outwardly to provide said bypass function.
 5. A propulsion systemas in claim 2 wherein each of said units comprise a casing and the meansfor pivotally mounting said units includes trunnion means having axesdisposed at the intersection of the axes of said pod passageway and saidports, and further including means for sealing said unit ducts from saidports when they are registered with said pod passageway and sealing saidducts from said pod passageway when they are registered with said ports.6. A propulsion system as in claim 5 wherein: the pod, its passageway,the ducts and ports are circular in cross section; and the sealing meansare spherical.
 7. A propulsion system as in claim 2 wherein: each ofsaid units comprises a casing, a gas generator mounted remotelytherefrom, a fan rotor having a tip-turbine, means for ducting hot gasesfrom the gas generator to the tip-turbine and an annular discharge fromthe tip-turbine for the hot gases, and further including passagewaymeans in said pod with which the annular discharge of the upstream unitis registered in the horizontal position of the unit, therebydischarging the hot gases thereof to the exterior of the pod, and theannular discharge of the downstream unit is registered with the podpassageway in the horizontal position of that unit.
 8. A propulsionsystem as in claim 7 wherein: the pod, its passageways, the ducts andthe ports are circular in cross section, the inlet ports are formed on arelatively large radii after the nature of the bellmouth, the inlet tosaid pod passageway is relatively sharp for efficient entry of air athigh speed forward propulsion, the means for pivotally mounting saidunits includes trunnion means having axes disposed at the intersectionof the axes of the pod passageway and said ports, and further includingspherical means for sealing said unit ducts from said ports when theyare registered from said pod passageway and sealing said ducts from saidpod passageway when they are registered with said ports, covers for saidports which conform to the outer surface of said pod, means for pivotinginlet port covers to open positions when the units are in their verticalpositions, means for pivoting the discharge port covers about axesperpendicular to the direction of forward thrust when the units are intheir vertical positions, mEans for pivoting the discharge port coversin a rearward position toward a closed position so that they function asvectoring flaps in transitioning between vertical and horizontalpropulsion, means for pivoting the upstream unit to a horizontalposition during such transition while the other unit remains in avertical position blocking said pod passageway, bypass passagewaysextending at a low angle through said pod to its exterior intermediatesaid units to direct the fan discharge from the upstream unit to theexterior of the pod during transition, flap means normally closing thebypass passageways and means for swinging said flap means outwardly toprovide said bypass function.